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Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED '...

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At which stage is a transaction validated?

Let's say Alice owns 12 BTC in her wallet, and she tries to send 5 BTC to Bob. First the transaction is broadcast to all nodes, then transaction is in the transaction pool. Then miners would choose ...
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1answer
49 views

How will the Bitcoin wallet compute address?

I came to know that Bitcoin wallet will caluculate address from public key but I want to know how it will caluculate. After caluculating how will it know that address is redundant free.
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31 views

Is blockchain the only technology for p2p decentralised global network?

Are there any p2p decentralised cross border network structure out there?
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1answer
39 views

If you are building your own blockchain, how would you decide on the right consensus algorithm? [on hold]

Not limited to bitcoin. How does blockchain developers or businesses make the decision on which consensus algorithm to choose? What are the things to consider when deciding on the consensus ...
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My Bitcoin transaction timed out on CoinGate but payment/BC disappeared and merchant denies receiving it…how can I track it down?

So I sent a payment from my Blockchain wallet to a merchant late one night last week and found out in the morning it had "timed out" but the BC was gone and there was no option for a refund. ...
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0answers
16 views

Games to learn blockchain [closed]

Are there any games on Android platform available in India to learn the blockchain technology?
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0answers
18 views

Insight api bitcore node for Horizen (zen) is not running

I get this following error when I try to run insight api fro zen. I had a full node of Horizen (previously known as Zencash Zen) running so I was trying to install insight api on it. I made copied ...
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2answers
26 views

How is blockchain stored on disk?

Hi how is blockchain actually stored on disk? I noticed bitcoin uses key store database level DB but what is the structure? https://github.com/bitcoin-core/leveldb-old/blob/bitcoin-fork/doc/...
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18 views

Sending a Bitcoin Transaction with Pure PHP?

Does anyone know of a simple PHP script or library that will allow me to send bitcoin transactions without needing to download the blockchain? Basically I just want to be able to use a private to ...
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2answers
41 views

Is encryption really needed for blockchain to work?

Is it right to say that Bitcoin and other blockchains do not use encryption? I read somewhere that blockchains rely on digital signatures and hash functions but not on encryption, and that encryption ...
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0answers
22 views

How should i start learning code of any cryptocurrency? [duplicate]

I want to learn about the code of cryptocurrency with all it's features including POS and master node features, currently I have XSN code (stake-net coin) and i want to learn it so i can make use of ...
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2answers
36 views

Blockchain data storage

My learning on blockchain is mainly theory based. I have always been under the impression that blockchain is about data processing and data storage which I think this is where I am confused. I have ...
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2answers
36 views

data confidentiality on blockchain

How does blockchain promise data confidentiality when the data is not encrypted? Or data confidentiality is not part of blockchain feature?
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21 views

Hide the ID of confidential transactions in blockchain networks

For a confidential blockchain, suppose there are three people which join a series of transactions. To hide the number of transactions among them, they need to do some dummy transactions. Suppose the ...
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1answer
33 views

Is hashing an optional step to use with public key cryptography for blockchain

I am confused by the public key cryptography versions that I've read so far. Are the steps optional, dependable on the types of blockchain or they are referring to different methods? Version 1 =======...
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1answer
232 views

Why a flip a bin before hashing in this script?

From How can I make this PHP merkle root script recursive? function binFlipByteOrder($string) { return implode('', array_reverse(str_split($string, 1))); } Why a flip?
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0answers
35 views

Why Spectre has a “weak” liveness?

According to this article: (https://medium.com/@avivzohar/the-spectre-protocol-7dbbebb707b5) written by one of Spectre's author (Aviv Zohar), it is mentioned that Spectre has weak liveness. What is ...
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1answer
42 views

How do different implementations of the Bitcoin Cash client know which type of coin they're processing?

TL;DR: Where in this code does the SV client figure out that it's not processing an ABC blockchain? This image prompted my question. There are a couple different mutually incompatible (I am assuming ...
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1answer
28 views

How Spectre tolerates spam transactions?

Spectre is a DAG based (directed acyclic graph) distributed ledger (a structure as an alternative to blockchain based distributed ledger). Is there any mechanism in Spectre to prevent sending spam ...
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0answers
19 views

What are inherent privacy threats to blockchain?

I am currently aware of two privacy threats that are inherent to blockchain: Transactions can be linked through address clustering (Fergal Reid, Martin Harrigan. An Analysis of Anonymity in the ...
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1answer
36 views

Is there a way I can reach the owner of the wallet address

I mistakenly sent some bitcoins to a wrong address. The mistake was from the wallet address I was given. An extra letter was added, making the address 35 digits. Is there a way I can reach the owner ...
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1answer
98 views

BCH ABC testnet Faucet?

I want a bitcoin cash ABC chain (BCHABC) testnet faucet. Cause 15th Nov. onwards after a hard fork on bitcoin cash network existing bch faucets are not working. Even questions over here are also not ...
4
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1answer
295 views

Why would running a light node riskier and subject to more frauds than a full node? We don't NEED a full ledger, do we?

I've been reading on light node and many have pointed out that the light node doesn't have the full blockchain and is riskier because they can't verify the transactions fully. First, we can verify ...
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0answers
23 views

Why can't an ISP ban access to a blockchain network? [duplicate]

I read that blockchain sits on top of the internet and is decentralised. We still have to access the blockchain network via an ISP. Without ISP, we can't access the internet so why can't an ISP block ...
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0answers
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Sybil attack with IOTA?

IOTA is one of the DLTs uses DAG (Directed Acyclic Graph) as data structure. The solutions to attacks proposed by IOTA white paper seems unconvincing, in particular, in case of double-spending, it ...
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27 views

Cant get transactions in USDT (OmniCore) node

I send USDT transaction to my node (it confirmed by omniexplorer.info), but node cant see it (and balance is 0). I use this commands for transaction listing: omnicore-cli --conf=/path/to/bitcoin....
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1answer
82 views

Why is a “first seen” rule is used to pick a side in a honest split, instead of deterministic criteria? [duplicate]

I was just thinking, why nodes pick the first block they see when there is an honest split, instead of picking, for example, the one with the "best hash" (number further away from the difficulty cut)? ...
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1answer
40 views

how to see bitcoin blockchain and addressess for testnet [duplicate]

in my site the user has a link to check the transactions and his wallet address. right now I am using this: blockchain: https://blockchain.info/tx/#{txid} address_url: https://blockchain.info/...
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1answer
21 views

I am just wondering what are the methods which can hide all the transactions and also able to validate transactions in an block chain?

I am new to block chain and was looking at how block chain work mainly proof of stake based . They check validity by going through all the transactions which is something concerning as everyone can ...
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0answers
24 views

logic behind bitcoin exchange [closed]

Im currently working on exchange program. Just a problem during exchange process. An example, we have an SELLING LIST which list down all trading and selling of bit coin. So, in the meantime, there ...
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0answers
17 views

Calculating Transaction Size for TestNet

Does it matter if I'm on the testnet in terms of calculating transaction sizes? I'm failing to comprehend the size calculation. Some are saying 180 * inputs Others are saying 148 * inputs For ...
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1answer
48 views

Is there a reward or penalty for validators in proof-of-stake (PoS)?

In PoW consensus, if a miner could solve the puzzle, they receive some monetary reward (some coins) to incentive miners, since mining process has a considerable monetary cost for miners including ...
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3answers
49 views

Block Validation: who does it? How much it costs? And is it present in all protocols?

Different threads were posted in order to clear up this question, but there are some points that I would need to confirm: When you become a full-node (NOT miner, you just downloaded the full ...
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1answer
58 views

Relation between bitadress and blockchain

When i create a wallet at bitaddress.org i could see my balance at https://www.blockchain.com/explorer . If bitadress.org is a client sided page and shouldn't send any information to outside world ...
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1answer
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What happens to a node if .bitcoin/chainstate is corrupted?

I tried to search for answers to my questions, but didn't find any, but please forgive me if this is a duplicate question. Suppose somehow .bitcoin/chainstate gets corrupted, e.g., a UTXO is deleted. ...
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1answer
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Does a transaction always get verified/processed by ALL full nodes in the network before being added into the block by some mining node(s)?

If not, then why is it often claimed that the blockchain scaling issue is due to the fact that all tx has to be verified by all full nodes? As long as a mining node found the correct nonce, the tx ...
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2answers
23 views

Number of main chain in a blockchain network

I just have a very basic doubt. Suppose there's a public blockchain network like Bitcoin comprising several nodes. Would it be possible that this network consists of multiple mainchains??I am not ...
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0answers
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How does the bitcoin network remove duplicate blocks being generated by multiple miners?

Say there are two minersA&B and each of them have produced the next block almost at the same instant. In this situation how is the network going to decide which one is the main block and abandon ...
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1answer
61 views

Converting xpub key to core format

I am experiencing some major issues which I honestly can't understand. When I am generating a wallet from Electrum the public key looks like this: ...
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1answer
31 views

How are transaction fees collected in Bitcoin? [duplicate]

I'm looking into the structure of blocks in the Bitcoin blockchain, and I can't figure out when\how the fees collected by miner of the blocks are transferred to the miner. According to what I can tell ...
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1answer
7 views

Is it required to broadcast the addresses generated locally to the bitcoin network?

Like the transactions are broadcasted to the bitcoin network , is it required that locally generated addresses also need to be boradcasted to the bitcoin network ?
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Can not sync litecoin

Yesterday I have run litecoin core to sync all blocks. I've done it several times because everytime when when the blocks got to about 776600, the litecoin stops syncing. I have already run litecoind ...
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1answer
24 views

Transaction is not Picked

I am new to block chain technology. I am struggling to understand below concepts: What if my transaction is not picked by the miners and what is the criteria for miners to pick? How can I rely on ...
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0answers
13 views

How can i list down blockchain data?

NOTE: I have already setup the full node I want to list down all transactions that occur on the bitcoin network (blockchain data) ? Is there is any django library that allow me to list down all the ...
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0answers
34 views

Which “Hyperledger Project” is more adaptable to be run on “micro-controller”?

Hyperledger has 5 different blockchains: (1) Hyperledger Fabric (2) Hyperledger Burrow (3) Hyperledger Indy (4) Hyperledger Iroha (5) Hyperledger Sawtooth Regarding the fact that micro-...
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1answer
72 views

Where are new addresses stored?

When a user generates an address using Bitcoin Core, is that address by default stored on the blockchain or will it only be stored after it is used in a transactions
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1answer
25 views

Explanation of Blockchain Payment systems [closed]

Trying as much as possible to understand what Blockchain technology is (As i am trying to see if i can be a Blockhain developer) and I just worked on a money transfer system myself and i hear everyone ...
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1answer
31 views

Unknown btc transaction

Could someone please explain what is this second transaction from the wallet 34UuFs8BtnbeJtdM9p4NBCHiP8MaD4f86n ? https://www.blockchain.com/btc/address/34UuFs8BtnbeJtdM9p4NBCHiP8MaD4f86n?filter=6 I ...
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0answers
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How to determine bitcoin wallet transaction direction (withdraw vs deposit)

I'm trying to programmatically process the transactions of my bitcoin wallet and to calculate my wallet balance, I need a solution in python, currently I'm using the blockchain.info, but if you know a ...
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0answers
32 views

Natural Language Processing and Blockchain?

This question is about one of the applications of the Blockchain in Artificial Intelligence. I am not very familiar with Natural Language Processing and I see that there is a Blockchain platform ...